Heat Treat Recipe HELP

T

Tyhuck

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Feb 15, 2014
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I was told that I might get more help if I asked my question in this section, so Im gonna try this again.

I know working with mystery steel is always a gamble, and that in order to get the best performance from a knife I would need to know the exact makeup of the steel. Well, to be frank, I cannot afford to have all of my steel tested. I get a large supply of used saw blades from a friend of mine that works at a mill. Most of the blades are 20" edger blades, and so far I have had pretty good luck making knives out of them. Up to this point, I have been using an oxy/ace torch for all my annealing and hardening, and my kitchen oven for tempering. The problems I've always had is not being able to achieve a proper annealed state because of a lack of ability to soak at temp, warping due to uneven heating, loss of carbon within the structure because of not being able to limit the oxygen in the immediate atmosphere, and uneven temper due to oven temps fluxuating. It is for those reasons that I recently invested in my own oven.

Now that I have the oven, I need to come up with some recipes that will work for my steels (I have used old files and rasps as well). I need suggestions on what kind of steel is most likely in the blades I'm using so I can figure out a workable recipe. Or, if anyone has determined a good recipe that works with saw steel, I'm more than willing to listen. I'm most interested in temps, soak times, etc.

I'm primarily looking for advise on the materials I have on hand, so please keep all replies within the realm of being helpful. Telling me to use known steel is not helping so please don't make suggestions to do so. I like the idea of using the old saws because it adds uniqueness to my knives that many potential customers like, especially being from East Tx. where timber is big business.

So, now I turn it over to your experience and expertise to help guide me along to make a better product.
 
Some could be L6, or a variant of L6. A lot are probably close to 15&20, which is basically a 1070-1080ish steel with nickel added. Or it could be a medium carbon steel if it's got carbide teeth welded on. In other words, "who knows"? You can learn a lot from playing with mystery steel, but it's always a gamble.

I'd start out by heat treating as if it was 15&20 and go from there. Thing about working with mystery steel is you've got to test, test, and test some more. And the recipe that works for one saw blade won't necessarily work for the next. Same is true of say L6 from different manufactures. If you've got a big enough blade you might send a chunk off for analysis, but most times it's not worth it. And manufactures often won't tell you what steel they use. I asked Woodmizer what steel was in there blades and they told me it was super top secret, as if I really wanted to know I couldn't have it analyzed.

Until I got an oven I never did have good luck with L6, it wanted to air harden to easily and even with a forge was a pain to get a proper aneal. Having an oven really opens up the possibilities and getting the most you can from the steel of choice.

I learned a lot playing with mystery steel, but even though I still sometimes use it, I don't use it much. I don't have time to screw around much with "wonder if this will harden", it's cheaper and easier to use a known steel.
 
I know it will harden because I have made several, and they have turned out pretty nice. I haven't gotten any complaints from my customers. I just have no idea what temperature Im getting it to when heating. I will look at the L6 specs, as well as some of the others you mentioned. I am mainly just looking for a starting point for my temps and soak times.
 
What about the files and the leaf springs? Any idea what are those most probably made of? I know its impossible to know without a test, but what would you start to treat it like?
 
Tyhuck said:
What about the files and the leaf springs? Any idea what are those most probably made of? I know its impossible to know without a test, but what would you start to treat it like?
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A lot of leaf springs are 5160 I think.
 
It's becoming more and more difficult to quess the steel compositions of springs . Here it wa s 5160 overseas often 9260 .Variations of these have been used and other alloys too. You could cut off a piece and see how it hardens.
 
The springs I have to use actually game off a couple of EZ-GO golf carts. One a 96, one an 86. Those are the only springs I have, so I wont be making too many out of the springs.

Still looking for suggestions on the files and rasps.
 
I was watching a ABS video and from what I can tell you have to do the work yourself. You have the steel in your possession so first thing to do is bring it up to say 1500 degrees and hold for a bit try 15 min and quench . If it hardens then its time to start working on your tempering. Start with say 400 degree's for a couple hours x 2 and put a edge on it and see what it does on a deflection test. If it chips bump it up 25 degrees and try again. Find its sweet spot and there you have it.

Problem is as posted above is every time you have a new piece you have to go through same procedures. If you insist on using unknown steels you are the only one that can solve these problems. So my suggestion is to get it hard and go from there.
 
Thanks. I understand that, and as far as hardening, Im slowly gathering enough information to get to where I need to be to start experimenting. The main concern I have is annealing. Once I get my blanks cut out, they are extremely hard on my sanding belts if I don't anneal them, and with the torch it seems like an incomplete anneal as they are still hard in the center. Plus, they are a PITA to drill. I just need an idea of what temps to heat to in order to get a good anneal. Would just heating to 1600 be good enough, or is it possible to overheat during the annealing process?
 
Files can be 1095, W-1, or Surface hardened mild steel. Rasps can be similar with more of them surface hardened. By the time you do any experimenting to figure out how to HT what you have you could have heat treated 4 or 5 blades from known steel. A bar of known steel might cost you $20, or a little more if you go exotic materials. 3/16x 1 1/2x72 1095 HRA is $19.15 plus shipping at admiral. I would recommend New Jersey Steel Baron though. Bit more expensive but he stands behind his material. You can get a lot of knives out of a 6 foot piece of steel..
 
I understand that, but people like the fact that my knives are made from recycled materials. Since this isn't my main source of income, I don't mind playing around with it. That's all part of the fun. Im just looking for some guidance from the guys that have been there and done that before, so Im not stumbling around blind.
 
Tyhuck said:
Thanks. I understand that, and as far as hardening, Im slowly gathering enough information to get to where I need to be to start experimenting. The main concern I have is annealing. Once I get my blanks cut out, they are extremely hard on my sanding belts if I don't anneal them, and with the torch it seems like an incomplete anneal as they are still hard in the center. Plus, they are a PITA to drill. I just need an idea of what temps to heat to in order to get a good anneal. Would just heating to 1600 be good enough, or is it possible to overheat during the annealing process?
Click to expand...

Try this one procedure for grain-carbide preparation and annealing;
1600 °F then air cool until black and quench to room temperature;
1500 °F then air cool until black and quench to room temperature;
1450 °F then air cool until black and quench to room temperature;
1200 °F (still magnetic) for a long soak into the oven (30 min.--1 hour) or for repeated times....then air cool; now you should be able to file, sand, drill etc...

now hardening:
prepare 3 little sample with the same previous conditions and try quenching from 1550, 1500, 1475 and compare the results after 2x 380 °F temper cycle, each one followed by water quenching.
 
Ok. I'll try that. My main concern is the fact that I have worked out a deal with an electrician I know to make him a knife out of an old file he has in exchange for him setting up the 220v service for my oven. I want to make sure I don't screw up his knife because the steel is a mystery.
 
Have you tried asking your buddy to find out what brand of blades they use then calling that company or one of their distributors to find out what steel they make their blades out of? They might vary the type of blades they use but my experience is that they typically have one brand/manufacturer that would be preferred and used most of the time
 
The problems I've always had is not being able to achieve a proper annealed state because of a lack of ability to soak at temp, warping due to uneven heating, loss of carbon within the structure because of not being able to limit the oxygen in the immediate atmosphere, and uneven temper due to oven temps fluxuating
Click to expand...

goggle muffle furnace Tai Goo
 
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